The primary objective of the study is to determine the feasibility of three-dimensional ultrasound as a more accurate and noninvasive means of determining human left ventricular function in patients with normal or abnormal ventricular function. Three-dimensional echocardiograms (3DE) will be compared with conventional two-dimensional echocardiograms and with cardiac magnetic resonance (MRI) evaluations of left ventricular cavity size and systolic function in men and women.